Nowadays, we usually hear "regroup" in subtraction in lieu of
"borrow." I guess borrow is an old fashioned word. I was taught by
the borrowing method (about 1939) working from right-to-left (borrow,
subtract; borrow, subtract). But many students I tutor regroup from
left-to-right. After they finish the entire regrouping process, they
begin their subtraction.
I don't dictate the method to the kids I tutor, if they know what they
are doing.
Problem is, the subtraction regrouping process is often not understood
by many of the students I tutor and many of them use the modern
left-to-right process which I suppose is mathematically correct. Many
students mark up the problem so severe, I can't see what the original
problem is and neither can they.
If anyone is interested I prepared a PowerPoint (jpg) picture and
posted it on my small web site that shows both methods. Comments are
welcome.
http://members.aol.com/loydlin3/borrow_regroup.jpg